This invention relates to machines for inserting mail pieces into envelopes and is directed more particularly to improvements in transporting the inserts or mail pieces along the insert track or raceway.
Business machines of the class commonly referred to as inserters are also referred to as envelope handling or stuffing machines. They are generally constructed and arranged for relatively high speed cycling for the gathering, collating, and inserting of mail pieces into envelopes. Examples of such equipment are illustrated in detail in the U.S. Pat. No. 2,325,455 to Williams which relates to a multi-station inserter. Another such example is illustrated in U.S. Pat. No. 3,306,606 to Sather et al which is directed to a multi-station inserter having an insert track or raceway which can reverse its direction of movement.
Such inserters have one or more insert stations with a stack of inserts at each station. Mechanical grippers withdraw the bottom insert from each stack of inserts and drop them onto a stationary insert track in front of a pair of pins or lugs on a driven chain. The chain is intermittently moved past the several insert stations and is momentarily stopped in front of each station as a new insert is dropped onto the track. As the lugs move past the insert stations, the inserts are collected in a pile which is then stuffed or inserted into an envelope.
As the number or thickness of the inserts increase, there is the possibility of inserts in one pile on the track overflowing or inadvertently falling into the succeeding pile on the track. An effort to alleviate this problem has been to provide adjustable hold-down members which can push down the inserts after they are withdrawn and deposited onto the insert track. These hold-down members are adjusted to a fixed height above the track to hold the pile down at a certain thickness as the pusher fingers move the pile of inserts towards the next insert or stuffer station. In some inserters, however, the number of inserts deposited onto each pile of inserts on the track may vary. Since the height of successive piles of inserts varies, the use of hold-down members which are adjusted to a fixed height above the stack has been found to be unsatisfactory.
In addition, there has been some difficulty in keeping thin, tissue-type inserts in their own insert piles as the number of inserts in a given pile increases. This is due to the flimsiness and lack of body of the thin insert. More specifically, the hold-down member compresses the pile of inserts resulting in substantial friction between the hold-down member and the top insert in the pile of inserts. Additionally, due to the compressive force of the hold-down member, there is substantial friction between the bottom most insert in the pile and the stationary insert track. This friction must be overcome by the lugs as they attempt to push the pile along the insert track past all of the insert stations and into the stuffing or insertion station. It has been found that as the number of inserts increases, and if there are one or more thin or flimsy inserts, these thin inserts have a tendency to not overcome the start up friction of the thin insert against the hold-down member. This is aggravated by the fact that the thin insert lacks the body strength to resist buckling or folding. As the lugs push the pile of the inserts along the track to the next insert station, the top, thin insert, tends to stick to the hold-down member or to buckle. This results in either a machine jam of the inserts or the insert is erroneously moved into the next pile of inserts. Should the misdirected insert be personal or confidential, the results could be disastrous.
Similar problems result from a thin insert being at the bottom of the pile of inserts. Here, the insert rests on the insert track and must overcome the friction between its bottom surface and the stationary insert track each time the pile moves. Thus, if the friction is not overcome, the insert, due to its flimsiness, buckles. Again this results in machine jams or misdirected, misplaced or lost document inserts. Thus, it is an object of the present invention to provide an improved inserting machine which has means to maintain thin or flimsy inserts in the pile of inserts in which they are deposited.
It is another object to provide an improved inserter in which there is provided an improved inserter hold-down member which reduces friction between the uppermost insert in the pile of inserts and the hold-down member while the inserts are moved along the insert track.
Yet another object is to provide an improved inserter which reduces the friction between the bottom-most insert of a pile of inserts and the insert track.